The present invention relates generally to a device for reducing aerodynamic drag on vehicles such as trucks and trailers and, more particularly, to an inflatable device for rounding the upper corners and edges of a vehicle.
Many vehicles such as trucks and trailers are constructed in a substantially box shape. The passage of such a vehicle through the atmosphere creates a large amount of drag from parasitic turbulence and various low and high pressure areas, thereby causing increased fuel consumption by the vehicle. These areas include an area of high pressure at the front of the vehicle, areas of low pressure at the top, sides and rear of the vehicle and areas of parasitic turbulence at the corners and edges of the vehicle.
Increased fuel economy can be had by constructing the vehicle with rounded surfaces and edges. Examples of these types of vehicles are disclosed in U.S. Pat. Nos 1,880,844; 2,159,671; 2,858,580; 3,163,435; 3,253,855; 4,468,061; 4,727,814; 4,767,132; and Reissue No. 25,914. However, this type of construction is generally expensive and tends to limit the effective volume that can be utilized in most applications.
Various devices may be retrofitted to a vehicle at low cost to decrease aerodynamic drag without decreasing effective vehicular drag. Rigid devices to round the front of a vehicle are disclosed in U.S. Pat. Nos. 4,022,508 and 4,036,519. In addition, inflatable devices to round the front or rear of a vehicle are disclosed in 2,737,411; 3,814,472; 3,934,922; 4,030,779; 4,057,280; 4,088,362; 4,688,841; 4,702,509; 4,707,015 and 4,741,569.